20912965 has 4 divisors (see below), whose sum is σ = 25095564. Its totient is φ = 16730368.

The previous prime is 20912923. The next prime is 20912989. The reversal of 20912965 is 56921902.

It is a semiprime because it is the product of two primes.

It can be written as a sum of positive squares in 2 ways, for example, as 3323329 + 17589636 = 1823^2 + 4194^2 .

It is a cyclic number.

It is not a de Polignac number, because 20912965 - 2⁹ = 20912453 is a prime.

It is a Duffinian number.

It is a self number, because there is not a number n which added to its sum of digits gives 20912965.

It is a congruent number.

It is an unprimeable number.

It is a polite number, since it can be written in 3 ways as a sum of consecutive naturals, for example, 2091292 + ... + 2091301.

It is an arithmetic number, because the mean of its divisors is an integer number (6273891).

Almost surely, 2^20912965 is an apocalyptic number.

It is an amenable number.

20912965 is a deficient number, since it is larger than the sum of its proper divisors (4182599).

20912965 is an equidigital number, since it uses as much as digits as its factorization.

20912965 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 4182598.

The product of its (nonzero) digits is 9720, while the sum is 34.

The square root of 20912965 is about 4573.0695380674. The cubic root of 20912965 is about 275.5107422994.

The spelling of 20912965 in words is "twenty million, nine hundred twelve thousand, nine hundred sixty-five".